Overedge sewing machine apparatus

ABSTRACT

A looper, bent in a direction crossing a sewing needle and having a special thread-catching part in a bent tip part, is fitted to a crank fitted to an oscillating looper shaft of a sewing machine. A middle part of the looper performs a vertical oscillating motion to make an overedge stitch and seam sewing on the side edge of a needle plate with a link mechanism borne on a swinging rod pivoted at one end. Means for oscillating the shaft of a sewing looper for making a seam and means for reciprocating the shaft and looper in the axial direction are fixed directly to a flywheel shaft without using any universal joint or the like, so that a seam may be made. The shaft of a driving gear for driving the shaft of the looper for the seam sewing is extended to be a shaft for the overedge stitching looper so that overedge stitching and seaming may be made with one flywheel shaft.

United States Patent [72] Inventors Susumu Fukutomi 6-32, 3 chome, Minaminagosaki Toshima- Masayoshi Koseki, Karasuyamajutaku No. 831, 818 Karasuyomamachi, Setagaya-ku,

both of Tokyo, Japan [21] App1.No. 800,391 [22] Filed Feb. 19, 1969 [45] Patented Oct. 5, 1971 [32] Priority July 23, 1968 [33] Japan [31] 43/53216 [54] OVEREDGE SEWING MACHINE APPARATUS 3 Claims, 11 Drawing Figs.

[52] U.S.Cl 112/162 [51] Int. Cl D05b 1120 [50] Field of Search 112/162, 163, 199,200, 192, 269

[56] References Cited UNITED STATES PATENTS 472,094 4/1892 Willcox et a1 112/269 Primary Examiner-James R. Boler Attorney-Irving M. Weiner ABSTRACT: A looper, bent in a direction crossing a sewing needle and having a special thread-catching part in a bent tip part, is fitted to a crank fitted to an oscillating looper shaft of a sewing machine. A middle part of the looper performs a vertical oscillating motion to make an overedge stitch and seam sewing on the side edge of a needle plate with a link mechanism borne on a swinging rod pivoted at one end. Means for oscillating the shaft of a sewing looper for making a seam and means for reciprocating the shaft and looper in the axial direction are fixed directly to a flywheel shaft without using any universal joint or the like, so that a'seam may be made. The shaft of a driving gear for driving the shaft of the looper for the seam sewing is extended to be a shaft for the overedge stitching looper so that overedge stitching and seaming may be made with one flywheel shaft.

PATENTEU um SIB?! v 8.610.187

SHEET 2 ur 6 PATENTED um 51971 SHEET 5 [1F 6 PATENTEU um 5 mm SHEET 8 [IF 6 OVEREDGE SEWING MACHINE APPARATUS BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates to an apparatus for making an overedge stitch and a seam, and particularly to a technique whereby the seam and a sewing looper are provided for sewing and seaming a plurality of cloths.

2. Description of the Prior Art To understand the present invention, the conventional techniques of a sewing machine for making an overedge stitch and of a sewing machine for making a two thread chain stitch shall be explained.

The conventional sewing machine for making an is usually provided with two loopers as a device for carrying a thread borne by a sewing needle below a cloth onto the cloth. One of the loopers moves in a direction at right angles with the line of a seam from a needle to the cloth edge and below the cloth, and the other one of the loopers moves to cross the needle onto the cloth so that, by the interplay of these loopers, the thread may pass over the cloth edge end and a so-called overedge stitching may be obtained. Because the two loopers must be moved to synchronously correspond to the vertical motions of the respective needles, it is difficult to adjust and coordinate the motions of the loopers and the mechanism is very complicated. Moreover, the incomplete or wrong adjustment of the motion of the looper will cause a skipped seam or incomplete sewing and will impair the function of the device. Also, the frictional stress of the entire device may become so great that the parts forming the device are likely to be worn. Such conventional overedge-stitching machines have problems in function, operation, handling and durability.

A so-called two-thread chain stitch to sew and seam a plurality of cloths is a comparatively complicated apparatus wherein a universal joint mechanism is employed to reciprocate the shaft of the looper in the axial direction, and at same time oscillate it in order to have the looper make an elliptic motion along a plane crossing the sewing needle. The general problems related to the above-described device also apply to this device. When using a universal joint or the like, problems in the adjustment and maintenance of its motion and timing occur, and increased cost and effort are required for its manufacture and maintenance.

The problems inherent in such a device are greater in a edge sewing machine wherein edge overedge stitching of cloths can be sewn and seam with one device, because in such machines the problems of the looper operating mechanism itself, the problems on the sewing looper, and the problems in the case of combining these mechanisms will be compounded.

SUMMARY OF THE INVENTION The present invention provides a sewing machine apparatus which includes a link-type looper-operating device having a first rod connected to an eccentric rotary device fixed to a fly wheel shaft. A reciprocating operating rod is connected to the first rod. The reciprocating operating rod is arranged so that a thrust shaft may rotate between engaging fixing pieces provided to project on the thrust shaft associated with a sewing looper. A moving gear is connected to the thrust shaft so as to be engaged with a wide pinion secured coaxially with a looper gear engaged with a driving gear connected to an eccentric rotary device on the flywheel shaft. An overedge-stitching looper bent in a direction causing a sewing needle has a thread-catching portion in its bent tip part and is pivoted in its intermediate portion to a swinging rod and in its base portion to a swinging crank fixed to a looper shaft. The looper shaft is coaxially integral with the shaft of the looper gear.

The present invention also provides overedge sewing wherein the thread caught in a needle hole in the tip portion of a reciprocating sewing needle is caught on the rear side of the needle by a looper below a needle plate. The thread is then raised over the edge of the cloth being sewn and is caught on a sewing needle falling down by crossing the rising sewing needle on the front side. The looper is again lowered so that the loops of the thread of the looper and the thread of the needle may be crossed and meshed with each other.

Applicant has discovered that by changing the structure of the thread-catching portion of the looper, a jointing sewing in butt jointing two pieces of material can be accomplished by the exactly identical looper operation. The present invention has been made by also taking into consideration the interchangability of the overedge looper and the seam looper.

The objects of the present invention are: to simplify the looper operating mechanism of a sewing machine for special uses; to provide a device which can keep the motion of a looper accurate and to thereby improve the function of the sewing machine; to provide a mechanism which can reduce the volume and weight of the entire apparatus so that the apparatus may be made smaller; to smooth the operation of the apparatus; to improve the durability of the apparatus; and to provide an apparatus wherein an overedge stitch and a seam can be carried out with one looperoperating device.

BRIEF DESCRIPTION OF THE DRAWINGS The structure and operation of the invention will be understood from the explanation of one embodiment made with reference to the accompanying drawings, wherein:

FIG. 1 is an elevational view of an interlocking sewing machine with the outer surface partially removed so that the internal structure may be observed.

FIG. 2 is a partial elevational view showing a link mechanism in a looper device for making an overedge stitch.

FIG. 3 is a bottom view of the interlocking sewing machine with the bottom part opened so that the internal structure may be observed.

FIG. 4 is a plan view of the internal structure.

FIG. 5 is an elevational view of the structure shown in FIG. 4.

FIGS. 6A (l)(ll), 6B (1)(6) and 6C (I)-(6) are schematic views showing the interplay and relationship between various loopers and a sewing needle.

FIG. 7 is a perspective view of an overedge-stitching looper.

FIG. 8 is a perspective view of a jointing looper.

FIG. 9 is a schematic view showing the interrelation of an overedge-stitching looper and a sewing looper with a sewing needle.

DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1, a flywheel shaft I is set within a sewing supporting mean's'or casing 2 and projects out of the side of the casing 2. To the projecting portion of flywheel shaft 1 there is fitted and fixed a flywheel 4 provided integrally with a pulley 3. Flywheel shaft 1 is the first means of transmitting power to various mechanisms of the sewing machine. To the flywheel shaft 1 there are fitted several eccentric rotary devices for transmitting reciprocating motion power to a sewing needle 5, loopers 6 and 7, and other mechanisms. To the eccentric rotary device can be applied a crank and an eccentric wheel. However, to the eccentric rotary devices 8, 9, 10, 11 and 12 there are applied eccentric wheels. (Hereinafter the eccentric rotary devices 8, 9, I0, 11 and 12 shall be called respectively eccentric wheels 8, 9, II), II and 12.) All the eccentric wheels 8, 9, 10, 11 and 12 have the flywheel shaft I passed through the shaft holes and are engaged with the flywheel shaft 1.by means of such keys 13 as in FIG. 5.

Among the eccentric wheels, the eccentric wheel 8 is gripped by a rod 15 for reciprocating the sewing needle 5; the eccentric wheel 11 is gripped by a rod 17 for reciprocating a cutter l6; and the eccentric wheel 12 is gripped by a rod 18 for operating a cloth feeding device (not shown). The gripping part of the rod is a ring which is split into two parts to be made integral while gripping the eccentric wheel by means of screws 19.

Because the present invention relates primarily to the looper related with the eccentric wheels 9 and I0 and its operating mechanism, the various mechanisms related with the eccentric wheels 8, l1 and 12 will be discussed only as required to facilitate understanding the present invention.

The looper 6 (partially shown in FIG. 1) is an overedgestitching looper set in a part which is positioned just below a needle plate 20. The mechanism carrying looper 6 is a link mechanism as shown in FIG. 2. Its structure will be explained with reference to FIG. 2. An oscillatable crank is fitted at its bottom portion to a looper shaft 22 by means of swinging crank shaft hole 23 and secured on the looper shaft 22 by means of a key 24. A fitting ring 26 located at one end of the looper 6 is pivotally joined to the other end of the swinging crank 21 by means of a screw 25. In addition, a fitting ring 27 formed in the middle of the length of the looper 6 is rotatably secured to an oscillatable rod 29 by means of a screw 28.

Thus, the looper 6 forms part of a link mechanism together with the oscillating crank 21 and swinging rod 29 and is fitted so that, in response to the oscillating motion of the swinging crank 21, the looper 6 may rise through the side edge of the needle plate 20 from below the plate and vertically oscillate to cross the sewing needle 5.

The looper which will now be explained is for overedge stitching. Its detailed form and structure are shown in FIG. 7. According to FIG. 7, the looper 6 has the above-described two fitting rings 26 and 27, is bent above the fitting ring 27, and has a thread-catching part 30 in its bent tip portion. The thread-catching part 30 has a hook 31 twisted and projected on the side of the looper 6 and a thread-catching hole 32 on the side of the root part of the hook 31.

The looper forming a link mechanism of the swinging crank 21 and rod 29 includes a seam-sewing looper 33 as is shown in FIG. 8. The same as the above-described overedge-stitching looper 6, this looper 33 also has two fitting rings 26' and 27, is also bent above the fitting ring 27', and has a thread-catching part 30' in its bent tip portion. The difference between the loopers 6 and 33 is in the thread-catching part 30. That is to say, the thread-catching part 30 of the looper 33 has no thread-catching hole 32 as in the looper 6, but instead has an expanded part 34 in the root part of the hook 31' and has a thread-catching 35 provided through the expanded part 34.

One of the important features of the present invention resides in the relation between the sewing needle and the loopers 6 and 33. That is to say, shown in FIG. 9 are an edgestitching looper 6 and a sewing looper 7. When the plane in which the looper 6 reciprocates vertically is set vertically, the sewing needle 5 should be so set as to cross the plane as inclined to keep an angle aand the looper 6 should be so set as to vertically alternately contact both sides of the needle tip. In such case, the cloth to be sewn is fed from right to left as viewed in FIG. 9. These things are exactly the same also with respect to the looper 33 shown in FIG. 8.

One vital aspect of the invention resides in the combination in one device of the above-described overedge-stitching looper looper 6 and sewing looper 7 (see FIGS. 1 and 7). The sewing looper 7 will now be explained. As shown in FIG. 1, the looper 7 is fixed to an oscillatable rod 38 having a slit 36a formed at the rear end and fitted to a thrust shaft 37 so that the shaft hole may be tightened with said slit 36a and a fastening screw 36b. A pin 39 and a screw hole are provided on the centerline of the tip part of the rod 38. The looper 7 is provided in its bottom end with a pin-engaging notch 40 for mating with pin 39, is provided with an elongated fixing hole along its lengthwise direction, is bent in the tip part, and has an arcuate thread-catching slot 41 the opposite end of which provide two thread-catching abutments. The looper 7 is integrally fixed to the rod 38 by means of screw 14, fixing hole and screw hole by engaging the pin 39 of the rod 38 with the pin-engaging notch 40 of the looper 7 so that the screw hole and the fitting hole of the looper 7 may coincide with each other. To determine the position of the thread-catching slot 41 of the looper 7, it is necessary to vertically adjust the setting position of the looper with respect to the rod 38 by means of the abovementioned elongated fitting hole through which is passed the screw 14. The looper 7 is fitted to the thrust shaft 37 as described above so as to move elliptically in a semicircular plane parallel with the thrust shaft 37 reciprocating in the axial direction and at the same time oscillating, as hereinbelow described, and within contact and cross the front and back of the sewing needle 5- below the needle plate 20 as shown in FIG. 9.

The internal mechanism for operating the looper described above shall be explained in the following.

The mechanisms of the devices for driving the looper shaft 22 and the thrust shaft 37 (FIG. 1) are shown in detail in FIGS. 3, 4 and 5. These mechanisms are contained and set within the casing 2 which includes a bracket arm 43 for fitting the sewing needle and a bed 42 as shown in FIG. 1. FIG. 3 shows the driving mechanisms set within the casing 2 as observed from the bottom of the casing 2. As shown in FIG. 3, a rod 44 is connected at one end to the eccentric wheel 9 on the flywheel shaft 1, and is connected at the other end by a connecting bolt 47 to a crank 46 of a gear shaft 45 arranged parallel to the flywheel shaft 1. The gear shaft 45 is carried in bearings 71, has a driving gear 48 affixed thereto near its intermediate portion, is reduced in cross section in the part crossing the other mechanisms, and is returned to its full circular cross section in the part inserted in the bearings 71.

A bevel gear is employed as the driving gear 48 engaging with a small looper pinion 49. For the looper pinion 49 there is employed a bevel pinion responding to the driving gear 48. This looper pinion 49 is fixed to the end portion of a shaft 51 supported in a bearing 50 on the casing 2. A wide pinion 52 is fixed between the looper pinion 49 and the bearing 50. The shaft 51 is extended out of the casing 2 to be connected integrally with the looper shaft 22. The oscillatable crank 21 is fixed t0 the end of the looper shaft 22 (see FIGS. 2 and 3). A gear 53 secured to the thrust shaft 37 with a screw 72 is engaged with the wide pinion 52. A sector gear is employed as the gear 53 to oscillate within the tooth setting range formed as a sector.

The thrust shaft 37 is arranged to be slidable in its axial direction in the casing 2. FIGS. 4 and 5 show the thrust shaft 37 in detail. According to FIGS. 4 and 5, the thrust shaft 37 is slidably mounted in a bearing 54 screwed to the the casing 2 and has-a reciprocating rod 55 fitted to it. A screw 56 affixes the bearing 54 to the casing 2. The reciprocating rod 55 has a fitting tube 55a and a rod shaft tube 55b. The thrust shaft 37 is rotatably inserted in the fitting tube 550 which is connected so as not to slide in the axial direction of the thrust shaft 37 by being held between two engaging fixing pieces consisting of collars 58 and 59 fixed to the thrust shaft 37 by screws 57.

A rod shaft 60 is inserted in the fitting tube 55b and is secured within it by a screw 73. This rod shaft 60 is inserted in the rod tube 62 of a rod 61, and is engaged with a flange 63 screwed in at the end so that the rod tube 62 may be prevented from being pulled out. The rod 61 is connected at its other end to the eccentric wheel 10 by a ring split into two parts adapted to be drawn together by the screws 19.

In FIG. 1, there is shown a needle bar 64 secured to and depending from the mounting bracket 43. The needle 5 is slidably supported and guided by the bar 64.

The operation of the apparatus according to this invention will now be explained as follows.

When the flywheel 4 is rotated by the pulley 3, the flywheel shaft 1 secured to the flywheel 4 rotates. By the rotation of the flywheel shaft 1, all the eccentric rotary devices affixed to it are also rotated. In response to the rotation of the eccentric wheel 9, the rod 44 fitted to it reciprocates to operate the crank 46 of the gear shaft 45. The motion of the crank 46 is an oscillating motion which causes the gear shaft 45 to oscillate. By the oscillating motion of the gear shaft 45, the driving gear 48 fixed to it oscillates, and the small looper pinion 49 engaged with the driving gear 48 also oscillates. In response to the oscillating motion of the looper pinion 49, the shaft 51 oscillates together with the looper shaft 22 and the wide pinion 52. By the oscillation of the looper shaft 22, the crank 21 swings to vertically reciprocate the looper 6. As the looper 6 is borne in the middle by the rod 29, the thread-catching part 30 of the looper oscillates from below the needle plate to above the needle plate 20 via its side edge. The threadcatching part of the looper 6 crosses the sewing needle 5 on the rear side of the needle when below the needle plate 20, and crosses the needle 5 in front of it when above the needle plate. This is exactly the same also with looper 33. FIG. 6 illustrates the sewing needle 5, looper 33 and thread-catching in the order of the progress of sewing. The looper 33 catches the thread from the sewing needle 5 when needle 5 is beneath the needle plate 20, and carries the thread upward over the edge of the needle plate 20. The thread is caught in the threadhanging groove 35 of the looper 33, and is carried until the looper 33 crosses the sewing needle 5 before it. The sewing needle 5 catches the thread carried from below by the looper 33. Then the looper 33 releases the thread while falling down. By repeating this operation, a seam as shown in FIG. 6B(6) is obtained. By using a thread-slipping base 70, a space sufficient to butt the edge ends of the cloths is given to the loops.

When the wide pinion 52 on shaft 51 oscillates the moving gear 53 engaged with it also oscillates to oscillate the thrust shaft 37. As a consequence of this motion, the looper 7 swings oscillates.

In response to the rotation of the eccentric wheel 10 connected to the flywheel shaft 1, the rod 61 reciprocates to reciprocate and slide the thrust shaft 37 in its axial direction via the reciprocating rod 55 and the collars 58 and 59.

Therefore, by the reciprocation in the axial direction and the oscillation around the longitudinal axis of thrust shaft 37, the looper 7 makes an elliptic motion in a semicircular plane parallel to thrust shaft 37 and crosses the sewing needle 5 alternately on the front and rear sides, as shown in FIG. 9. The so-called two-thread chain stitch sewing is accomplished by this movement of the looper 7, as shown in FIGS. 6C(1) through (5). The result of such sewing is depicted in FIG. 6C(6).

According to the present invention, in each of edge overedge stitching seam sewings, two loopers are not required but only one looper performs a motion required for the sewing. Therefore, there is no need to employ a complicated mechanism for operating two loopers and the structure is greatly simplified which contributes to making the apparatus small. In addition, because the apparatus is simple and only one looper is used, it is easy to maintain the accurate motion of the looper. Further, according to the invention, the mechanism is simple, operates smoothly, and possesses great durability.

We claim:

1. A sewing machine operating apparatus comprising,

supporting means,

a reciprocal sewing needle mounted on said supporting means,

a movable overedge stitching looper associated with said sewing needle and having a threading catching portion to move across said needle,

a first and driving shaft,

a first eccentric on and driven by said driving shaft,

an oscillatable gear operatively connecting said first eccentric to said stitching looper to move the latter,

a second and driven shaft mounted on said supporting means, said second shaft mounted to oscillate about its axis and also to reciprocate axially,

a second eccentric on and driven by said driving shaft and operatively connected to said driven shaft to reciprocate the latter,

a sewing looper mounted on said driven shaft and associated with said needle, said sewing looper having a threadcatching portion, and

a gear fixed onto said driven shaft in mesh with said oscillatable gear to effect oscillation of said driven shaft and having a sliding relation with said oscillatable gear axially of said driven shaft.

A sewing machine operating apparatus as defined by claim 1 means for mounting said sewing needle inclined at a predetermined angle to the plane of reciprocation of said overedge stitching looper to allow said overedge stitching looper to cross the path of said sewing needle alternately on opposite sides of said sewing needle in the rise and fall positions of said sewing needle.

3. A sewing machine apparatus as defined by claim I including a third and oscillatable shaft carrying said oscillatable gear, for rotation therewith, said third shaft journaled on said supporting means, and a crank on said third shaft operatively connected to said overedge stitching looper. 

1. A sewing machine operating apparatus comprising, supporting means, a reciprocal sewing needle mounted on said supporting means, a movable overedge stitching looper associated with said sewing needle and having a threading catching portion to move across said needle, a first and driving shaft, a first eccentric on and driven by said driving shaft, an oscillatable gear operatively connecting said first eccentric to said stitching looper to move the latter, a second and driven shaft mounted on said supporting means, said second shaft mounted to oscillate about its axis and also to reciprocate axially, a second eccentric on and driven by said driving shaft and operatively connected to said driven shaft to reciprocate the latter, a sewing looper mounted on said driven shaft and associated with said needle, said sewing looper having a thread-catching portion, and a gear fixed onto said driven shaft in mesh with said oscillatable gear to effect oscillation of said driven shaft and having a sliding relation with said oscillatable gear axially of said driven shaft.
 2. A sewing machine operating apparatus as defined by claim 1 means for mounting said sewing needle inclined at a predetermined angle to the plane of reciprocation of said overedge stitching looper to allow said overedge stitching looper to cross the path of said sewing needle alternately on opposite sides of said sewing needle in the rise and fall positions of said sewing needle.
 3. A sewing machine apparatus as defined by claim 1 including a third and oscillatable shaft carrying said oscillatable gear, for rotation therewith, said third shaft journaled on said supporting means, and a crank on said third shaft operatively connected to said overedge stitching looper. 